Strip chart recorder



y 1950 G. KEINATH 2,516,217

STRIP CHART RECORDER Filed Dec. 9, 1944 7 Sheets-Sheet 1 mdmmwm INVENTOR Geo rye/(6074M.

BY a

u y 5, 1950 G. KEINATH 2,516,217

STRIP CHART RECORDER Filed Dec. 9, 1944 7 Sheets-Sheet 2 INVENTOR. Geozye Kai/74172. BY

July 25, 1950 G. KEINATH 2,516,217

STRIP CHART RECORDER Filed Dec. 9, 1944 7 Sheets-Sheet 3 IIIIIHI lhllllllll /IM 8L- INVENTOR.

6 A." M. Y ca e ezrm 25, 1950 KElNATH 2,516,217

STRIP CHART RECORDER Filed Dec. 9, 1944 7 Sheets-Sheet 6 2/ Fly 15. &E 'm l 24 Impulse Z Transmitter Impulse 3 Transmitter 7:00 7:ao 5:00 6:30 y- LLLL.-... L. I

F2318. INVENTOR.

George/(einalh BY W2;

Patented July 25, 1950 UNITED STATES PATENT OFFICE STRIP CHART RECORDER George Kelnath, Larchmont, N. Y.

Application December 9, 1944, Serial No. 567,356

15 Claims. 1

My invention relates to recording apparatus for measuring and supervising purposes.

It is among the objects of my invention to devise recorders which are capable of providing a plurality of strip chart records and lend themselves readily to being used for greatly diversified measuring purposes while requiring relatively simple, reliable and space-saving apparatus as compared with the recorders heretofore known for similar purposes.

Another object of the invention is to provide recording apparatus capable of producing a plurality of strip charts for recording a plurality of magnitudes of simultaneously occurring phenomena and to render such apparatus especially suitable for studying or supervising the various conditions involved in the operation of manufacturing and processing plants, and it is also an aim of my invention to provide a multiple operation recorder as just mentioned which, despite a large number of different records to be taken thereby, occupies sufficiently little space to permit designing it as an ambulatory or portable device.

An object of my invention is also to devise a recording apparatus for multiple strip chart records which contains only one pen or stylus member for producing the different records.

A further object of the invention aims at providing a recording apparatus for the supervision of industrial equipment or machines, which by means of a relatively simple mechanism, produces a record not only of the on and off periods of the equipment or machine but, within the same chart or diagram, also of an output quantity, energy consumption, or other determinant of the working condition during the on periods.

These and other objects of the invention will be apparent from the following description in conjunction with the appertaining drawings in which:

Figure 1 is a partial front view of a multiple strip chart recorder according to the invention;

Fig. 2 is a sectional side elevation of the same recorder;

Fig. 3 shows diagrammatically another embodiment of a strip chart recorder according to the invention and represents the essential parts plicable as part of a recorder otherwise designed as shown in Figs. 1, 3, 6, 7 or 8;

Fig. 6 is a schematic illustration of a further embodiment according to my invention, and Fig. 7 represents the electric circuit diagram appertaining to the apparatus of Fig. 6;

Figs. 8, 9 and 10 are diagrammatic showings of three further modifications, respectively, of recording apparatus according to the invention;

Figs. 11 through 14 exemplify diiferent kinds of strip charts obtainable with recorders as shown in the preceding figures.

Fig. 15 represents a side elevation of a recording apparatus similar to that shown in Figs. 1 and 2 but especially designed for indicating differential magnitudes.

Figs. 16 and 1'7 exemplify further strip chart records of the kind obtainable with apparatus according to the invention;

Fig. 18 represents a chart as obtained in a switch position recorder of the type shown in Fig. 18a;

Fig. 19 is an explanatory circuit diagram of a control device applicable for recorders as shown in preceding figures; and

Figs. 20 and 21 show further examples of obtainable chart records.

Referring to Figs. 1 and 2, the frame structure of the illustrated recording apparatus has two parallel plates l and 2 interconnected by a cross piece 3. A shaft 4 is journalled between the plates l and 2 and carries a metal cylinder 5 for accommodating and advancing a recording sheet 6 which, in the illustrated embodiment, is sufllclently wide to receive twelve strip charts denoted by Sl', S2, S3 Sill, SH, SH. When in operation, the shaft 5 is driven by a suitable motor or clockwork (not shown) so as to revolve in the direction of the arrow Al proportional to time thereby advancing the sheet 6 in the direction denoted by the arrow A2.

A worm shaft 1, also journalled between plates I and 2, extends in parallel to shaft 4 and is provided with a cross-pitch thread which returns into itself near both ends of the cylinder 5. A sleeve-shaped carrier 9 is slidably mounted on shaft 1 and has a pin In in engagement with the thread 8. A projection 9a of carrier 8 engages a bar 9b (Fig. 2) which extends between the plates I and 2 and prevents the carrier 9 from rotating. Hence, when the shaft 1 revolves, the carrier 9 and its pin l0 are displaced by thread 8 along the cylinder 5. Upon reaching either end of thread 8, and without change in the revolving direction of the shaft 1, the carrier reverses its direction of travel. The shaft I may be driven continuously in the direction indicated by the aeiaaiv arrow A3 by means of a suitable motor or clockwork, or by a gearing between shafts d and T1 (not shown). In this manner, the carrier 9 reciprocates repeatedly along the cylinder durstylus electrode when an electric voltage is applied between this electrode and the metal cylinder 5. Such application of voltage is obtained and controlled by twelve control devices of which those visible in Fig. 1 are denoted as a whole by DI, D2, D3, Dlll, DH and DII, respectively.

These control devices, in the embodiment of Figs. 1 and 2, are of similar design so that it sufflees to refer in the following to details of only one of them.

A shaft I3 is firmly mounted on plates I and 2. Control device Di has an insulating cylindric body or drum l4 revolvably seated on shaft l3 and held in position relative to cylinder 5 so that the axial extent of body ll corresponds to the width of the strip chart SI. A metal wire I5 is embedded in the peripheral surface of body I4 and forms a single-tum helix whose pitch corresponds to the axial extent of body I. A spur gear I6 is firmly secured to body I4 and meshes with a gear I]. Gear I1 is firmly attached to a ratchet l8 and revolvable about a shaft [9 which is firmly secured to the plates l and 2. A driving pawl engages the ratchet II and is operated by the armature 2| of an electromagnet whose control coil is denoted by Cl. Each electric current impulse applied to coil Cl causes it to advance the ratchet I! one step thereby rotating the body It and its contact helix ii a given angle.

As'mentioned, the other devices, such as those denoted by D2, D3, D", D and DIZ, are designed and operative in a similar manner so that each excitation of the respective coils C2, C3 CIO, CH and Cl2 causes a corresponding rotation of the apertaining contact helices. The control devices thus function independently of each other, each controlling the angular position of the helix allotted to one of the twelve strip charts of sheet 6.

The twelve insulating cylindric bodies (such as body l4) and the appertaining contact helices (such as helix ii) are serially aligned in proximity to one another so that control contact l2 of carrier 9 engages the bodies sequentially when travelling back and forth along the series of bodies I. The helices l5 are all in conductive connection with shaft l3; and this shaft, in turn,

- is connected to a voltage source, schematically indicated at 22, whose other pole is connected to the cylinder 5, it being understood that one or both of parts l3 and i are insulated-from the plates I and 2. when the carrier 9, upon leaving 'the'left-hand end of its path travels along shaft 1, the contact pin l2 rests against the insulating surface of the cylindric body I 4 of device Di until the pin passes across the contact helix I. At the moment of this passage the circuit of source 221s temporarily closed, and a voltage appears between stylus II and cylinder 5. As a result, a dot mark is produced on the electroresponsive sheet 6 within the area of strip chart Si. As

the carrier 9 passes through the range of device D2, another recording mark is produced by the a stylus at the moment when contact pin 02 passes through its point of registry with the contact helix of this second device, and this second mark appears on sheet 6 within the area of strip chart $2. In the same manner, further marks are inscribed in the other strip chart areas until the carrier reaches the other end of its path. Upon reversal of its travel, the procedure is repeated in the opposite direction. Since during many reciprocations of the stylus carrier the sheet 6 advances slowly in the direction of arrow A2, a

series of recording marks is produced in each of the twelve strip charts so that each strip receives a record curve of the type exemplified by curves RI, R2 and R3.

The point of registry between contact pin l2 and the contact helix of each control device depends on the rotary position of the helix and hence is shifted once through the width of the appertaining strip chart for each full rotation of the helix.

The twelve devices DI Dl2 may be controlled independently of one another by any suitable means for transmitting impulses to the control coils Cl (H2 in accordance with the magnitude of the respective phenomena to be studied. Two such impulse transmitters are exemplified in Fig. 1 and denoted, as a whole, by Ti and TH.

Transmitter TI' is designed as a production counter for determining the output quantity of a machine or other plant unit. A conveyor belt, advancing in the direction of the arrow A5, passes the work pieces 26, 21 from the machine or unit along a counter 28 whose register is advanced one step each time a work piece meets the actuating member 28 of, the counter. .A cam 29, driven by the counter, lifts and drops a movable contact 30 once for a given number of counted pieces thereby switching contact 30 from a stationary contact 3i into temporary engagement with another stationary contact 32. A current source 33, connected with a current limiting resistor 34 maintains a capacitor 35 in charged condition as long as contact 30 is dropped. When contact 30 is temporarily lifted, the capacitor 35 is disconnected from source 33and instead connected across coil CI of control device DI. Now a discharge current passes through the coil and causes it to advance the helix mechanism. Consequently curve RI on strip chart SI represents counted output versus time.

The transmitter T l2 includes a meter 38 for measuring the kilowatt hour (kw. h) consumption of a machine or other plant unit under supervision. The integrating register of the meter is provided with a cam 31 which controls the charge and discharge of a capacitor 38 in a manner similar to that of transmitter Ti. Transmitter Tl2 is connected to coil CI! of control device Dl2. Consequently, the contact helix of device Dl2 revolves one step for each given amount of power consumption. and the curve marked on the chart represents integrated values of such consumption versus time.

A multiple recorder as described above, operating at a substantially constant speed of the stylus transport shaft 1. produces recording marks when traveling in both directions of reciprocating motion. The marks consecutively produced on the individual strip charts SI through Sl2 of sheet 8 have substantially equal spacing only in the centrally located strips, while in the border strips, such as SI and Sl2, two successive record points follow each other closely and nearly a full cycle period elapses before the next two marks appear. With the total width of sheet amounting to 250 mm., for instance, and with a period of 20 seconds for a full cycle of stylus reciprocation at an advancing speed of 60 mm./h. for the sheet, the virtually coinciding two record points on strip charts SI and S|2 are about mm. apart from the next point in the advancing direction of the sheet. This spacing is satisfactory for a large variety of recording purposes. However, it is also within the scope of my invention to provide recorders, designed and operative in accordance with similar principles, which secure an equal time spacing between successive recording marks on all strip charts. It is further possible to render the stylus operative only during alternate half cycles of reciprocating motion and to perform the then idle return stroke at a higher speed than the working stroke in order to obtain an approximately uniform timing or continuity of the recording operations. The apparatus shown in Fig. 3 exemplifies the justmentioned modifications. Fig. 3 also illustrates a simplified mechanism for driving the stylus or pen member of the recorder and shows diagrammatically an electrically operating system for controlling the operation of the recorder.

According to Fig. 3, the shaft 44 of cylinder 45 is driven by a motor MI in proportion to time. Cylinder 45 accommodates a record sheet 45,

movable contact located in the path of the stylus carrier near the ends of this path. The movable contact is normally biased toward open position but when entrained by the stylus carrier engages a stationary contact thus closing temporarily an energizing circuit for either relay CR| or CR2.

Relay CRI has its operating coil 55 connected between main Y and limit switch LI, the latter being in turn connected to main X. Three contacts 51, 55 and 55 are controlled by coil 55. Relay CR2 has its coil 10 connected between mains X and Y through limit switch L2 and is equipped with two contacts H and 12. A push button contact l3, biased to normally open position,- permits energizing the coil 55 of relay CRI in order to start the operation in a manner to be explained hereinafter.

The marking operation of stylus 5| is electric as in the embodiment of Fig. 1. The marking circuit extends from main X, through shaft 5! to each of the contact helices 55, thence through control pin 52, as the pin travels across each helix, to stylus 5|, through the electro-responsive sheet 5 and cylinder 45 to contact 55 of relay here shown for receiving six strip charts S| through S5, and advances the sheet in the direction of the arrow A2. In contrast to the recorder of Fig. l, a single-thread feed screw 41 serves to move the carrier 45 with its stylus 5| and contact pin 52 along the cylinder. Six control devices similar, for instance, to device D| in Fig. 1, are provided for controlling the marking operation of the stylus within the range of the six strip charts or width portionsof sheet 45; however, only the six appertaining helix drums are shown in Fig. 2. These six drums are loosely aligned on a common shaft 53 and have each an insulating cylindric body 54 with a single-turn contact helix 55 and a transmission gear 55, these parts being similar to those denoted in Fig. 1 by |4, |5 and i5, respectively. The three shafts 44, 41 and 53 are mounted on a supporting structure (not shown in Fig. 2).

The feed screw 41, in order to reciprocate the stylus carrier, must alternately be revolved in opposite directions. To this end, the screw is connected to the armature 50 of a reversible electric motor M2 whose field windings 5| and 52, wound for opposite rotation of the armature, are alternately energized under control by two limit switches L| and L2 with two appertaining control relays CRI and CR2 respectively. Winding 5|, when energized, causes the armature 55 to move the stylus carrier 49 in the working direction at a speed selected by means of an adjusting rheostat 53. Winding 52, when energized, causes the carrier to perform its return stroke. A field weakening resistor 54 is provided to obtain an increased speed of return motion thus reducing the duration of the idle stroke to a minimum. The motor M2 and the appertaining resistors are connected to the mains X and Y of a current supply line controlled by a main switch 55. The connection extends through contacts of the two relays CRI and CR2, still to be described. The

same mains may also serve to feed the sheet transport motor MI, preferably through a speed adjusting rheostat SR.

The two limit switches LI and L2 have each a CR|, and main Y. This circuit is closed at contact 59 only when relay CRI has picked up. Contact 58 of the same relay controls motor winding 5| for moving the stylus relatively slowly along its working stroke. Consequently, the stylus performs its marking operation only during'this working stroke and runs idle when passing rapidly through its return stroke.

The operation of the recorder as a whole is as follows: closure of switch 65 places the apparatus in working condition, but when stylus carrier 49 assumes a position, as shown in Fig. 2, between limit switches Ll and L2, the coils and I5 0! both relays CRI and CR2 are deenergized and .the motor M2 remains at rest while the sheet transport motor MI starts operating. When now the start button 13 is depressed, a circuit is closed from main X, through contact ll, button 13, coil 65, to main Y. Relay CRl picks up and closes at contact 61 a self holding circuit through contact 1|. Therefore, relay CRI remains energized after button 73 is released. Contact 55 puts voltage on motor winding 6| so that armature starts driving the stylus carrier in its working direction toward limit switch L2; and contact 69 closes the marking circuit so that the stylus is operative to produce a series of record points on sheet 6 as described in the foregoing. At the end of the working stroke, carrier 49 closes the limit switch L2. Now coil 10 becomes energized and relay CR2 picks up thereby opening at contact 1| the self sealing circuit of relay CRI. Consequently, relay CRI drops off and, at contact 61, closes a self sealing circuit for coil 15 of relay CR2. Thus, relay CR2 remains energized in circuit X, ll, 51, 10, Y after limit switch L2 is subsequently opened. In this manner, motor winding 60 is deenergized and the marking circuit interrupted, while motor winding 52 is-energized and causes the stylus carrier 5 to run rapidlv and electrically idle toward limit switch Ll. When carrier 9 hits upon the switch, coil 55 of relay CRI is again energized. Contact 51 opens the self-sealing circuit of relay CR2 and prepares a self-sealing circuit for relay CRI which, immediately afterward, is completed at contact ll of dropped-off relay CR2. As a result, the motor M2 is reversed and another working stroke started. This performance repeats itself until the main switch 65 is opened. The time constants of the relay operation can be so chosen,

if desired that both motor windings BI and 62 are simultaneously energized for a short interval during each reversing operation in order to brake the motor by plugging. However, other automatic braking means may be employed instead. One or both of the limit switches LI and L2 according to Fig. 3 may be made displaceable along the path of travel of the stylus carrier 9. This permits selecting one strip chart or any number, less than the available total, of consecutive strip charts and helix drums to be scanned by the stylus assembly. In this manner, when only one or a few strip chart sections of the multiple recorder are to be used, the stylus may be caused to travel only across the one or several selected strip charts and to reverse its motion as soon as the scanning of the selected helix drums is completed. This aifords not only a reduction in the time needed for each complete sweep motion of the stylus but contributes also to better continuity of the marking operation performed by the stylus.

Reverting to Fig. 1, it will be noted that the electromagnetic drives of the control devices DI BIZ and the appertaining measuring devices exemplified by impulse transmitters TI and TIZ, are designed for counting or integrating measurements. However, it is one of the characteristics of my invention that the adjustment of the devices for controlling the marking operation of the pen or stylus is not limited to a particular type of control but can be performed in response to any phenomenon capable of being translated into and measured by, a corresponding mechanical motion regardless of whether this motion is obtained by a direct deflection method or some follow-up or other indirect method. This will be understood from the following description of the embodiments of my invention shown in Figs. 4 through 8.

Figs. 4 and 5 illustrate a control device, denoted as a whole by DH and shown in Fig. 5 together with an adjacent control device DM of duplicate design, which permits recording deflection measurements and is intended to be inserted in a recording apparatus of the type shown in Fig. 1 or 2 instead of any of the devices Di Dl2 previously described. That is, the insulating cylinder or drum 14 with its contact helix l5 and spur gear 16 is revolvably seated on a shaft l3 and corresponds, for instance, to cylinder M in Figs. 1 and 2. A sector gear Tl meshes with spur gear 16 and is mounted on the, shaft 18 of an armature 19 disposed between the pole faces of an electromagnet 80. Shaft 18 is journalled between two non-magnetic plates 8|. If the helix is designed for 360 revolution (full-turn helix), atotal rotation of the armature of about 80 may conveniently be chosen for this type drive. The terminals 82 of the magnet coil Cl3 are to be connected to a measuring circuit for supplying a direct current whose magnitude changes in accordance with the condition to be measured. A spring (not shown) is provided for biasing the armature assembly toward a position of rest so that the helix assumes a position of revolution determined by the ampere value of the current supplied through terminals 82 to coil C13 (or CH). Hence, the stylus, when passing through the position of registry with the helix, will produce a mark on the appertaining strip chart in a position indicative of the measured magnitude to be recorded.

While the control device of Figs. 4 and 5 will be recognized as operating according to a direct -manner described previously.

the recorder shown in Figs. 6 and 7 involves a follow-up method as regards the adjustment of the helix drum.

Referring to Fig. 6, the frame structure 83 01' a multiple recording apparatus carries the revolvable shaft 84 of a cylinder 85 for accommodating a recording sheet 86 and also the revolvable feed screw 8! for driving the carrier 89 of a stylus SI and a contact pin 92. Shafts 81 and N are driven by a constant speed motor M which may be controlled in the manner exemplified above in conjunction with Fig. 3. Another shaft 93 (Fig. 6) is firmly mounted on frame 83 and carries the helix drums of a number of devices, such as those located at Dl5 and DIS, for controlling the marking operation of the stylus in the The two strip charts of sheet 86 that are correlated to devices Dill and DIE are denoted by SIS and Sit respectively. The drive mechanism of device DIG, for instance, may be 'similar to any of those described previously. In distinction therefrom, device DIS includes a follow-up system designed as follows.

The drum 9%, revolvable about shaft 93 and provided with a contact helix 95 and a spur gear 96, is driven by a gear 9'! whose shaft 98 is connected to a reversible motor or driving unit M3. While it should be understood that the followup drive for the helix drum may be equipped with any suitable motor or drive mechanism of the reversible type, the drive unit M3 shown in Fig. 6 is designed, in accordance with a novel principle of my invention, to operate intermittently and stepwise. In the illustrated embodiment that is achieved by means of a ratchet gear 99 which is mounted on the drive shaft 98 and under control by two oppositely acting pawl members IE0 and IM, each having a magnetic armature I92 or N33 to be magnetized by a field coil Hi l or I85. The magnetic circuit of the armatures is preferably polarized by means of a permanent magnet not.

The energization of the coils I04! and M35 is controlled by an electric system (Fig. 7) which includes an adjustable potentiometric rheostat whose slide contact l0! (Figs. 6 and 7) is firmly attached to the helix drum 96 so as to rotate together therewith. The rheestat has a stationary insulating base I08 (Fig. 6) secured to frame 83 which carries the appertaining potentiometric resistor 39 (Fig. 7).

The control system, as shown in Fig. 7, is composed of a Wheatstone bridge circuit BC and a relay circuit RC. Bridge circuit BC includes an impedance member H0 which varies its impedance value in response to changes of a condition 'under observation and, hence, represents the measuring gauge proper of the system. Another impedance member ill in circuit BC serves as a standard of comparison. Members ill! and Hi are arranged in a closed series connection with resistor I I19. The input diagonal across this connection contains a constant voltage source H2, and an interrupter I 13 here shown as a rotary contact device. The output or zero diagonal of circuit BC, extending from slider I01 to a point between members H6 and Hi, includes a polarized electromagnetic relay l It. The movable contact I I5 and two appertaining stationary contacts H6 and Ill of relay Hi are connected to coils Wt and H05 of the reversible drive M3. A parallel group of a capacitor 8 and a direct current source l l9 lies between contact H6 and coil lot. A similar group, containing a capacitor I26 and deflection method, one of the control devices of 15 a parallel connected current source l2l, is con= 9. nected between contact I" and coil I". When relay contact H is in the illustrated center position, the circuits of both coils III4 and I05 are open and the two condensers III and I 24 are charged by their respective current sources II! and IN.

During the operation of the system, the interrupter H3 is rotating and energizes circuit BC in regular intervals, for instance, every second for a period of half a second, these intervals and periods being chosen, in accordance with the requirements or desiderata of the intended application. With no current flowing in circuit BC, relay member 5 is In center position. It circuit BC is balanced when the interrupter II3 closes, the voltage across the relay diagonal remains zero so that member II5 retains the center position. When the bridge is unbalanced at the closure time of interrupter II3, an unbalance voltage appears across the coil of relay H4 and causes contact member Hi to engage either contact H5 or III depending upon the direction of the unbalance. This, in turn, causes capacitor I II or II9 to discharge through coil I04 or I05, thereby actuating one of the two pawls IIII, IOI (See Fig. 6) with the eifect of turning the ratchet wheel 89 and the helix drum 85 one step in the direction required for reestablishing the balance condition of circuit BC. When the unbalance persists at the next closure of interrupter II3, the drive M3 moves the helix drum another step toward the balance adjustment, and when the direction of unbalance changes the same operation comes into play except that it will then occur-in the opposite direction.

A follow-up system of the intermittently and step-wise operating pe as exemplified by the above-described apparatus of Figs. 6 and 7 is advantageous in cases where a low current consumption and/or a reduced switching duty of the relay are desired. Since the current in the bridge circuit flows intermittently and each time for a limited period only, the consumption is correspondingly low and an overheating of the gauge element IIII, consisting for instance of a resistance thermometer, is prevented even if the bridge current is so heavy that it would cause overloading it it flowed continuously. Excessive wear of the relay contacts is avoided because, upon each contact closure, the discharge current of the capacitors builds up gradually, due to the high inductivity of the field coils I04 and I05, thus reducing the switching duty imposed on the relay contacts. In addition, the illustrated provision of a polarized electromagnetic ratchet drive reduces the energy requirements for the relay circuit as compared with the use of ordinary unpolarized drives or power relays with two relay systems. These advantages are especially valuble for portable or ambulatory recording apparatus to be energized from dry cells or storage batteries.

A control device also applicable in apparatus according to the invention but operating in a manner different from that of the above-described helix drums, is embodied in the multiple recorder shown in Fig. 8 where several component portions of the device are denoted by DH. According to Fig. 8, the supporting frame structure I23 of the recorder has bearings for the shaft I24 of the cylinder I 25 for accommodating the recording sheet I26. Shaft I24 is connected to a motor MI to be driven in proportion to time. The sheet is wide enough to accommodate a plurality of strip charts such as those denoted by SIT, SI8 and SIS, A threaded shaft I21, driven by a motor M2, for instance in the manner and by the control means described above in conjunction with Fig. 3. engages with its threaded portion a carrier I29. A stylus electrode I3I and a control contact or pin are mounted on the carrier I32. Another shaft I33, stationarily mounted on the supporting structure I23 of the apparatus, extends in parallel to shafts I24 and I2! and serves as a seat for a number Of helix drums appertaining to control devices of the two types shown in Figs. 1, 2 and 4, 5. The device denoted in Fig. 8 by DIB has a step-by-step drive corresponding to the devices shown in Figs. 1 and 2 and serves to control the marking operation of the stylus along the width portion (strip chart) SI8 of sheet I26. The control device DI9 shown in Fig. 8 corresponds to those of Figs. 4 and 5 and serves to control the marking operation for strip chart SID. Devices DI 8 and DIS, together with any desired combination of additional devices of either type, are secured to the supporting frame I23 of the recorder.

The control device DH is provided for controlling the marking operation of the stylus when it traverses the width portion of sheet I26 occupied by strip chart SII. An insulating cylindric body' I34, forming part of device DH, is mounted on shaft I33 and carries a metal sleeve I35 of the same diameter as the contact helices of the other control devices DI8, DIS. However, cylinder I34 need not be revolvable and, preferably, is firmly seated on shaft I33. While the stylus I3I, during its marking stroke, travels across chart SII, the contact pin I32 of stylus carrier I28 is in sliding contact with the stationary sleeve I35. However, the marking circuit of which sleeve I35 forms part, is so controlled that it is energized only when the stylus passes through a point of travel indicative of the measured magnitude to be recorded. The means, appertaining to device DII, for achieving this controlled energization of the marking circuit will be described presently.

A coupling I36 connects the stylus feed shaft I21, through bevel gears I31 and I38, with the rotatable slider I33 of a potentiometer rheostat I40 which forms part of a Wheatstone bridge circuit BC containing a condition-responsive impedance member or measuring gauge HI and a standard impedance member I42. The bridge circuit is energized from a current source I43 and has its output diagonal or zero branch connected to the moving coil of a galvanometric relay I44. The movable contact I45 of relay I44 cooperates with two stationary contacts I46 and I4? to charge a capacitor I 48 from a current source I43 through a current limiting resistor I50 when contact I45 rests against contact I46, and to discharge the capacitor I48 through sleeve I35, contact pin I32, stylus electrode I3I, paper sheet I26, and sheet transport cylinder I25 as soon as contact I45 has switched over to contact I47.

When the stylus carrier I29 begins its working stroke in the direction of the arrow A4, the slider I33 starts simultaneously its rotary travel along rheostat I 40 in the direction of the arrow A6. Stylus carrier and slider move in synchronism, and slider I39 completes a full cycle of its rotation at the moment when contact pin I32 reaches the end of sleeve I35. At the beginning of this operation, the bridg circuit is unbalanced so that contacts I 45 and I" are separated. Consequently, the marking circuit is interrupted so that the moving stylus I3I is inoperative electrically. During its further travel, slider I39 passes through an angular position in which the impedance magnitude of measuring gauge I is bal- 11 anced by that of the standard impedance member I62. In this instant, the voltage across the zero branch passes through zero and reverses its polarity. This causes relay I to switch movablecontact I66 from contact I46 to contact Ill. As a result, the capacitor, previously charged through contact I66, is discharged through stylus electrode I3I and sheet I26. The discharge produces a recording mark on the sheet and exhausts itself so rapidly that the mark forms a point whose location, relative to the width of strip chart SII, indicates the instantaneous position of the stylus at the moment of bridge balance' and, hence, is representative of the corresponding angular position of theslider I39. Since the slider position depends on the impedance value of gauge Ill, the recorded mark is indicative of. that value and thus of the magnitude of the rheostat and relay arrangement is ineffecq tivev to produce recording marks during the rest of the stylus travel. Then, however, the successive engagement of theadvancing contact pin I32 with the helices of device D16, DIS, etc. is effective to temporarily close another marking circuit between the helices or their common shaft I33 and the sheet transport cylinder I25, as expossible to equip recorders with a stylus of any sultable'kind which is normally held away from the'sheet and is-forced electromagnetically.

or mechanically against the 'sheet at the points of stylus travel where a mark is to be recorded. This will be understood from the modification shown in Fig. 9 and described presently.

The details shown in Fig. 9 are applicable instead of the corresponding parts in recording apparatus otherwise designed in accordance with Figs; 1 and 2. Therefore, the reference numerals applied to Fig. 9 are the same as those of comparable parts of Figs. 1 and .2 except that a prime is added in Fig. 9. According to Fig. 9, the helix I5 projects from the cylinder or drum I 6' and forms a knife-edge at its periphery. The

- stylus carrier 9', engaged by the feed screw 1' .carries a stylus member II which is integral with a pin I2 and axially movable relative to the carrier s. A spring biases the pin I2 against I the'surface ofdrum I6 and holdsthe. point of stylus II normally away from the record sheet 6'. As the carrier 9' travels in the direction of the arrow Al, pin I2' will engage the projecting helix I5 at a point determined by the rotary ad- .justment of cylinder I6, and the helix will then force the pin toward the carrier 9" so that the stylus I I'v approaches and touches the sheet 6. The stylus produces a mark at the point of contact and then returns to its inoperative position.

'If an ink penor pencil stylus is used, the mark is produced merely by mechanical contact be- I I tween stylus andpaper. If the stylus is permaplained previously. It is, of course, possible to control governed by. suitably arranged limit switches of the type mentioned above in conjunction with Fig. 3 (such details being not shown in Fig. 8). It should also be understood that I consider the control rheostat and relay means of device DII, as described above, to be I representative of a large variety of difierent controlsystems of similar cyclical operation, such as those disclosed in my Patents Nos. 2,321,605 and V The contact sleeve I35 in Fig. 8 functions as a backing member or slide path for the control contact pin I32. The use of a sleeve placed on an insulating cylinder, as illustrated, has the ad- I vantage that the member can readily be placed on a common shaft with the backing members or helix drums'of the other control devices and Y secures a proper alignment of its slide path with those of these other members without requiring a critical angular adiustment. If. desired, however, the device DII may be'equipped with a backing member of different design, the only requirement being that it has a conductive and insulated slide path of proper length and location to be engaged by the control contact I32 as ittravels across the corresponding strip chart of the recording sheet. I

For the sake of simplicity and because I consider the use of electroresponsive record sheets recommendable in conjunction with my invention, only the method of marking by electric discharge i referred to in the foregoing. However, other electric or non-electric marking methods may likewise be used for recorders according to the invention. For instance, itis nentlyconnected to a current source, its contact with or suflicient approach toward the paper may also be used to mark an electroresponsive sheet substantially as explained in the foregoing. It is further possible to place a typewriter ribbon between'stylus and sheet in order to perform a mechanical marking operation.

Referring to Fig. 10, the multiple recorder partly shown in this illustration has four devices for controlling the marking operation within respective areas of the strip chart. These devices are denoted .by D26, D2I, D22 and D23 respectively but. are represented only'by the appertaining helix drums. These drums, such as the one denoted by I66, are aligned on a shaft I63 and have each helix member as shown at I65. The helix drums of devices D2I, D22 are revolvable about shaft I63 and are driven by gears such as those-denoted by I66, I61 and I66 so that when-drum I64 is driven by shaft I63, theother three drums will revolve at one tenth, one hundredth and one thousandth the speed ofdrum ing chart illustrated in Fig. 21..

Recording apparatus according the invention are especially favorable for the supervision of plants in which a large number of difierent magnitudes are to'be recorded in correlation to v one another. The invention facilitates taking such coordinated records by means of equipment of relatively small size and weight so that the equipment, if desired, may be designed as a portable or ambulatory unit. For instance, a recorder as shown in Figs. 1 and 2, or Fig. 3 may accommodate twelve charts, each about 20 mm.

wide on a sheet of about 250 mm. width. The

advancing speed of the sheet and the cycle period of the stylus can be chosen in accordance with the desiderate of each particular application.

Apparatus according to the invention are extremely versatile as to the various recordable phenomena and utter considerable advantages over the multi-pen recorders heretofore used for the supervision of plant operations not only toward better correlation between the diiferent diagrams but also as regards the accuracy or readability of the individual chart records. These advantages will be understood from the following description of some of the methods of application of my recorders.

Counting production or energy quantities It is often desirable to have a record of the production output of machines or other industrial equipment. In this respect, two data are usually of interest: (1) when was the machine running and when was it stopped? (2) what was the output or what was the energy consumption? Recorders have been built and used with from 12 to 20 recordings pens actuated by as many magnets for recording the on" and off periods of a group of machines. The diagrams obtained with these known recorders are of the type exemplified by the diagram a in Fig. 11. The illustrated diagram shows for a total period of one hour all interruptions in the operation of a machine under supervision but does not indicate whether the machine was running at reduced speed or under reduced load, or whether its output was insuflicient. In this respect, a recorder according to the invention conveys more comprehensive information within a single diagram. Integrating counters of the type shown in Fig. 1 at Tl or Tl2 together with stepwise operated helix devices, such as device DI in Figs. 1 and 2. are applicable for the recording purposes here in point. The strip chart diagrams produced by such recorders are exemplified by diagrams b and c in Fig. 11. Both diagrams are shown for the same number and moments of stoppage as the reference diagram a but indicate diiferent energy consumptions of the machine. The diagrams b and c are characteristic in that the record curve traverses consecutively the whole width of the diagram, advancing always in the same direction, and drops back to zero after a certain number of measuring units have been counted. Diagrams of this type show interruptions of the machine operation just as well as the diagram a, but they indicate also any slow-down or change in production output or energy consumption of the machine. For instance, diagram b is drawn for normal production within the hour of observation, while diagram represents an operation in which the production was below standard part of the time. According to diagram b the power consumed during the recording period (1 hour) was 24.2 kw. hr. With no stoppages, 40 kw. hr. would have been consumed. Hence the efficiency was 60.5%. According to diagram 0, 16.2 kw. hr. were consumed corresponding to an efliciency of 41.5%.

The number of impulses supplied by the impulse transmitters (Ti Ti 2 in Fig. 1) to the stepby-step drives is preferably so chosen, or the gearing between the step drive and the helix drums so rated that the recorded diagram includes a convenient number of complete crossings of the strip chart within a suitable period of observation and under normal operating conditions of the machines or other plant units under supervision. For instance, for one shift (8 hours) of normal production, a number of 50 completed crossings on a strip chart of, for instance, 20 mm. can conveniently be counted on a 1000 mm. line. Hence, it a machine output is normally 10,000, pieces per day, the helix control device may be made to rotate the helix drum once for each 200 counted pieces; or ii the machine output is only 2500 pieces per day, the control device may be chosen so as to obtain a full helix rotation for each 50 pieces or counting impulses. For less than 500 pieces per day in normal production, the helix can be made to rotate 360 for each 10 counting impulses, each impulse representing 2 mm. displacement of the recording mark across the width of the strip chart. With such arrangements, the recorded diagrams reveal at a glance the approximate output per given period by the number of crossings occurring within the period. Fig. 12 shows a typical strip chart corresponding to the last-mentioned example. The longitudinal axis of the chart indicates time, and each complete crossing denotes an output of 50 pieces so that the total output for any given period can easily be recognized. Irregularity of production and stoppages are also apparent from the diagram.

These principles of recorder operation can be applied to other integrating measuring operations such as the measuring and recording of gallons per time of fuel consumption, tons of steam per time, ampere hours, or other flow quantities.

Measuring time In conventional multi-pen recorders, the advancing speed of the chart determines the accuracy of the time reading. Assuming that one can accurately distinguish advance distances of 1 mm., a chart advance of 60 mm. per hour affords a reading accuracy of 1 minute. That is, intervals of 1 minute can still be distinguished satisfactorily.

In cases where a higher accuracy of time reading is desired, a recorder according to the invention can readily be made to reduce the readable interval to a small fraction of one minute.

0 this end, one of the helices of the recorder is driven at constant speed, for instance, by a stepby-step drive, such as the one denoted by D24 and T24 in Fig. 15 and described below, so that it performs one rotation, for instance, within seconds. Then, with a strip chart of 20 mm. width and a chart advance of 60 mm. per hour. the total travel of the stylus across the strip chart is 600 mm. per hour. Again, with a reading accuracy of 1 mm., one can now determine the duration of an operation to be recorded with an accuracy of six seconds. A time record of this kind is exemplified by the strip chart shown in Fig. 13. The chart shows that an operation under supervision started at time point Pi and ended at point P2. Since, in this example, each complete crossing denotes 120 seconds the interval of operation between Pi and P2 was eight minutes and fifty seconds. The second operating period, between points P3 and P4, lasted five minutes and twelve seconds; and the duration of the third period of operation is recorded, between points P5 and P6, as three minutes and six seconds.

Recording diflerential or uniformity values anaarr ber of five crossings will appear, but these crosschange in the course of the recorded curve. Ac-

cording to Fig. 14, a protractor-type transparent gauge B can be placed on the chart for determin ing the curve angle directly in terms of approximate percentile departure from the standard production value.

A more accurate method, especially suitable in cases where the production or energy magnitude,

to be moved is usually nearly uniform and varies only occasionally a few percent, consists in the use of a helix drum in conjunction with a reversible differential drive. Any control mechanism capable of rotating the helix drum in opposite directions in accordance with the direction and extent of the difference between two measuring magnitudes is applicable 'for this purpose. One of the available possibilities is illustrated in Fig. 15.

The recorder portion shown in Fig. 15 is substantially similar to that of Fig. 2 in particular as regards those parts which are denoted by the same reference numerals as in Fig. 2. Ifhe recorder of Fig. 15' is different only in having two control devices D24 and D25, each designed like any of drives Di through D12 in Figs. 1 and 2, which act on the same ratchet gear 18' for driving the helix drum 14 in opposite directions. To this end the pawl tooth, which is controlled by the armature of device D24 and engages the teeth of ratchet gear, is shaped so that it slides ineffectively over the ratchet teeth when the armature of device D24 is attracted and pushes the ratchet gear clockwise when thereafter the armature is released. In contrast thereto, the corresponding pawl tooth of device D25 is shapedto pull the ratchet gear counterclockwise when the armature of device D25 .is attracted but slides idle over the ratchet teeth when thereafter the armature is released. Each control device is actuated by a separate impulse transmitter T24 or T25. One of the transmitters T24 operates as a production counter like transmitter Tl in Fig. 1 or as an energy or flow counter like transmitter T12 in Fig. 1. The other transmitter T25 in Fig. 15 issues impulses in proportion to time.

, If, for instance, the production to be supervised is supposed to be 10,000 pieces or measuring units in eight hours, the time-proportional transmitter T25 is adjusted to issue 9. corresponding number of impulses in equal intervals of time during the eight hour period. Hence 1250 time measuring impulses are issued per hour, or 21 impulses per minute. If the helix drum performs one full revolution for 200 impulses, this would amount to 2% of the normal production of the eight hour shift and would produce 50 crossings on the appertaining strip chart if the second control device remained inoperative during the entire shift period. However, since the second control device, in response to the actual output, is also working and acts in opposition to the timeproportional drive, a smaller number of crossings will appear on the chart. Thus, if the counted production stays 10% behind normal, only live crossings will appear on the chart during the eight hour period; that is, each crossing is completed in about 1.6 hours. If the counted ings are slanted in the opposite direction. No

crossing will appear if the production staysuniformly on the desired value. In summary, the slanting direction of any crossing marked on the chart indicates whether the productionis higher or lower than normal, and the number of crossings indicates the number of pieces or other counting units gained or lost during any selected period oftime. p A typical diagram of this type is shown in Fig. 16. Changes in uniformity of production of only one or a few percent can easily be" recognized on a strip. chart of only 20 mm. width.

The same principle is applicable for various other differential measuring operations. For instance, for recording a. supposedlyconstant speed of a machine, the speed is translated into a given number of impulses per revolution which are sup-1 plied to one of' the differentially operating control devices. The other control device is provided with the normal number of impulses per length of time.

The resulting diagram is also of the type shown in Fig. 16 and reveals speed variations of a few percent.

- Recording trafiic Referring to Fig. 1, it will be understood that theelectric marking circuit for any of the strip chart sections may include a relay contact, like the one denoted by S in Fig. l, which permits interrupting the circuit between helix drum and sheet transport cylinder in response to the occurrence of a given condition, or which varies the stylus voltage by disconnecting the voltage source 22 (Fig. l) and substituting it by a source .22 of low voltage, thereby changing the thickness of the recording mark produced by the stylus. This possibility can be taken advantage of for recording on a strip chart a magnitude in addition to those otherwise recordable in a single chart diagram. This will presently be elucidated by way of example.

Whenusing a recorder according to my in--* vention, or one of its sections, for recording telephone traflic, a step-by-step drive (see T1 and D1 in Fig. 1) may be employed which rotates an appertaining helix drum (14 in Fig. 1) a given fraction, for instance, /10 or /20 of one revolution for each telephone call so that each complete travel of the diagram across the strip chart is o denoted in Fig. 17 by the dotted line portions.

periods.

The strip chart thus obtained indicates the number of calls during any selected period, the duration of each call, the time when each call was made, and the time and duration of the line free production is 10% above schedule, the same numvide a synchrotie or other mechanical or electromagnetic connection between the switch mechanism and the helix drum so that the helix assumes a rotary position corresponding to the posiemployed in connection with helix type recorders according to the invention in cases where a continuous temperature recording is not required. A limited number of temperature responsive relays, each set for a different temperature, are used for controlling the rotary position of the helix drum. This is exemplified schematically by the circuit diagram shown in Fig. 19. According to this figure, an armature I coacts with three field magnets I16, I11 and I18 each following having higher ampere turns than the preceding magnet. Each magnet is controlled by a thermostatic relay I19, I80, I8I, respectively, and connected to a current source I82. Relay I19 is set to close its contact at a temperature of, for instance, 65 F.; and relays I80 and I8I close at 68 F. and. 71 F. respectively. If the temperature to be recorded is below 65 F., none of the relays is closed so that the armature I15 is in the illustrated dropped ofi position. If the temperature is above 65 F. but below 68 F., only relay I19 is closed and the armature lifted up to magnet I18. If the temperature increases to a value between 65 and 68 F., the armature rotates another ste toward magnet I11; and if the temperature exceeds 71 F., all three relays close so that the armature moves another step toward magnet I18. A subsequent decrease in temperature causes the armature to shift in the opposite direction of rotation due to the sequential opening of relays I8I, I80 and I19. Armature I15 is connected by a suitable transmission with a helix drum I14 of the recorder. The diagram obtained in this manner is of the type shownin Fig. 20.

Recording decimal values In recorders according to the invention, two or more helix drums can be coupled with one another by transmission or control devices so that they are controlled in dependence upon a single variable control magnitude but operate at different speeds in decimal relation to one another like the number wheels of a counting register.

This is illustrated in the above-described Fig. 10 and will be elucidated by the example of apparatus for recording the water level in reservoirs. Three items are often of interest for such recording purposes: (1) a representation of the approximate level movement between zero and maximum values, (2) a record of the small daily or hourly movements and (3) a record showing the quantity of contents or change of contents with high accuracy.

The conventional level recorders are usually float operated. They have a chart of considerable width (500 mm. or inches wide) in order to afford fair reading accuracy. Compared therewith, a decimal hook-up between several helix drums of a recorder according to my invention does not only lead to smaller recorders but permits also an improved reading accuracy and a clear indication of minima and maxima. For instance, four helix drums, arranged side by side in the manner generally exemplified by Fig. 10,

are driven by a float I12 or other measuring devices, so that the helices perform revolutions of reversible direction in accordance with the changes in water level. One helix drum (D20 in Fig. 10) is arranged for fastest rotation so that a full revolution of its helix corresponds to, for instance, 10 mm; change in level. The next helix drum (D2I) is geared so as to revolve once for each 100 mm. changes in level. The third drum (D22) indicates 1000 mm. change by one full turn, and the fourth (D23) revolves once for a change of 10,000 m. The diagrams thus obtainable are of the type exemplified by Fig. 21. The strip chart S20 of the diagram indicates the approximate total level changes between zero and 10,000 mm. Strip charts S2 I, S22 and S23 represent the thousands, hundreds and tens digits, respectively, of the same changes. During periods in which the changes of level occur in the same direction, the charts S2I, S22 and S23 may show a series of crossings (only a few of such crossings are shown in Fig. 21). Each minimum and maximum is clearly marked and can be read off with high accuracy. The maxima and minima indicated in the diagram correspond to the millimeter values of level entered at the right-hand margin of the illustrated chart.

A decimal or digit principle of the aboveelucidated type is also applicable for any other measuring purposes where extreme reading accuracy is required with a chart of rather limited width.

It will be understood from the foregoing description that recorders according to my invention are applicable for a large variety of recording purposes and that differently designed control and recording devices can be employed in connection with the dilferent sections or helix drums of a multiple recorder. It will further be evident to those skilled in the art that several of the above-described features afford the intended advantages also if applied to drum type recorders or to recorders for a single strip chart,

and that other modifications and changes than those described can be made within the gist of my invention and without departure from the scope of the essential features set forth in the claims appended hereto.

What I claim is:

1. Apparatus for recording a variable magnitude of a condition under observation, comprising means for accommodating and moving a record chart; a stylus member disposed for producing recording marks on the chart and being movable across the chart in a direction transverse to the motion of the chart; a helical member revolvable about its geometrical axis and having an axial extent correlated to the width of said chart in said direction so that different angular positions of said helical member correspond to different respective points along said width of the chart; a scanning member movable axially along said helical member and connected with said stylus member for controlling the latter to produce a mark on the'chart when said scanning means pass through a point of engagement with said helical member; drive means for moving said stylus member and said scanning member cyclically and simultaneousl in a proportion to each other; and condition-responsive control means in driving connection with said helical member for adjusting its position 01 revolution in dependence upon the magnitude to be recorded.

2. Apparatus for producing a record on a chart; comprising a backing member for accommodating the chart; a carrier displaceable along said backing member and provided with a stylus for producing a record on the chart and a member for controlling the recording operation of said stylus; a rotary member having its axis of rotation extending parallel to the path of motion of said carrier and being provided at its periphery with helical means for causing said control member to render said stylus operative when said control member, during the displacement of said carrier, is in registering position with said helical means; means for rotating said rotary member in accordance with the magnitude of a condition to be recorded in order to thereby displace said position in parallel to said path; drive means for displacing said carrier; and means for advancing the chart relative to said stylus and at an angle to said displacement.

3. Apparatus for producing multiple strip chart records on a recording sheet, comprising means for accommodating and longitudinally advancing the sheet; a plurality of serially aligned devices each having a helical member revolvable about its geometrical axis extending transversely of the sheet and means for controlling the rotary position of said helical member so as to thereby place a selected point of said helical member in a given reference position relative to the appertaining width portion of the sheet; marking means having a member movable transversely of the sheet for sequentially scanning the selected points of said plurality of helical members and having a stylus member and movable simultaneously with said scanning member and controlled by said scanning member so as to produce a recording mark on the sheet each time said scanning member passes through its position of registry with one of said points.

- 4. Apparatus for producing multiple strip chart records on a recording sheet, comprising means for accommodating and longitudinally advancing the sheet; a plurality of serially aligned devices each having a helical member revolvable about its geometrical axis and allotted to a portion of the width of the sheet; a plurality of control means for adjusting the rotary position of said helical members respectively so as to place a selected point of each helical member in a given reference position relative to the appertaining width portion of the sheet; marking means having a scanning member movable along said plurality of helical members for sequentially engaging said helical members at said selected points respectively and a stylus movable in synchronism with said scanning member and transversely of the sheet, said stylus being controlled by said scanning member to produce on the sheet a recording mark each time said scanning member engages said helical members respectively; and drive means for periodically moving said scanning member along said plurality of helical members while moving said stylus across the sheet.

5. A multiple strip chart recorder, comprising a backing member for accommodating the chart; a carrier displaceable along said backing member and provided with a stylus for producing a record on the chart and a member for controlling the recording operation of said stylus; a plurality of rotary members having a common axis of rotation extending in parallel to the path of motion of said carrier and being each provided at its periphery with helical means for causing said control member to render said stylus operative when said control member, during the displacement of said carrier, passes through registering positions with said respective helical means; a plurality of means for revolving said rotary members respectively in accordance with a corresponding plurality of magnitudes to be recorded in order to thereby displace said respective positions in parallel to said path; drive means for periodically displacing said carrier; and means for advancing the chart at an angle to said path.

6. A multiple strip chart recorder, comprising a revolvable conductive cylinder for accommodating and longitudinally advancing an electroresponsive chart; a carrier displaceable along said cylinder, provided with a stylus electrode for producing recording marks on the chart when energized, and having a contact member electrically connected with said stylus electrode; a

plurality of insulatin members revolvable about a common axis parallel to that of said cylinder and serially aligned along said cylinder, each of said members carrying a contact helix for engagement by said contact members; a plurality of means for revolvin said insulating members so as to displace the point of contact engagement of said respective contact helices along the appertaining portion of said cylinder; drive means for periodically displacing said carrier so as to move it sequentially through the points of engagement of said contact helices; and electric means connected to said helices and said cylinders for energizing said stylus electrode when said contact member passes through the points of engagement with said helices.

'7. Apparatus for recording a variable magnitude of a condition under observation, compris ing means for moving a record chart at substantially constant speed; marking means disposed for producing a curve on the chart and including a single-turn helical member capable of successive full revolutions about its geometrical axis and having an axial extent correlated to the width of the chart transverse to the moving direction of the chart so that different positions of revolution of said helical member correspond to diiferent singular points respectively across the width of the chart; a unidirectionally operating step-by-step drive having a driving member and having a stepwise revolvable gear engageable by said driving member to incrementally revolve in always the same direction when actuated by said driving member, said helical member being constrainedly connected with said gear and exclusively controlled by said gear to revolve in only one direction, an impulse transmitting counting device connected to said driving member for causing said gear to unidirectionally revolve said helical member a plurality of full turns for a given plurality of counts.

8. Apparatus for recording a variable magnitude of a condition under observation, comprising means for moving a record sheet; sheet marking means disposed for producing a plurality of curve records on the sheet and having a corresponding plurality of serially aligned helix members revolvable about a common geometrical axis, said helix members having an axial extent correlated to respective portions of the sheet so that different positions of revolution of each helix member corresponds to respectively different points on the appertaining sheet portion; condition-responsive drive means connected to one of said helix memhere for varying its position of revolution in accordance with the magnitude of the condition under observation, step-down transmission means interconnecting said helix members so that each following member revolves a progressively smaller fraction of the revolution of said one member so that the recorded curve records represent respective digits of a single recorded magnitude.

9. Recording apparatus, comprising means for accommodating and advancing a chart; chartmarking means for producing a recording mark on the chart at a marking point along the width of the chart transverse to the advancing direction of the chart, said marking means having a revolvable member shaped as a single full turn of a helix whose pitch is correlated to the width of the chart so that different positions of revolution of said helix member correspond to respectively different marking points; two separately controllable control devices having drive means connected with said helix member for revolving said helix member in opposite directions respectively; condition-responsive measuring means connected with one of said devices for controlling it to operate at a variable average speed corresponding to the variation of a measuring magnitude; and program means connected with said other device for controlling the latter to operate at an average speed in accordance with a predetermined program magnitude; whereby the record produced by said marking means is indicative of the departure of the measured magnitude from said program magnitude.

10. Apparatus for recording a plurality of variable quantities on a record sheet, comprising means for accommodating and longitudinally advancing the sheet, an assembly movable transversely of the advancing direction of the sheet and having electrically operable stylus means engageable with the sheet for marking the sheet and having contact means electrically connected with said stylus means for transmitting mark producing impulse to said stylus means, drive means for moving said assembly periodically across the tion to the travelling direction of said assembly and engageable by said contact means so as to be sequentially contacted by said contact means as said assembly travels across the sheet and electric circuit means in connection with said members and said contact means for providing said impulses as said contact means engages said respective members, whereby said stylus means is caused to produce on the sheet a plurality of parallel strip chart records each forming a curve representative of one of the quantities to be recorded. 1

11. Apparatus for recording a variable magnitude of a condition under observation, comprising means for moving a chart at a substantially constant rate of motion, means disposed for marking the chart and comprising a plurality of control devices correlated to different surface portions of the chart to make a plurality of curve records on said surface portions respectively, means for controlling one of said devices in response to said magnitude, a reducing transmission connecting said one device with the adjacent device and being a transmission ratio of 1:10 for operating the latter at one tenth rate of operation of said one device, and additional reducing transmissions of a transmission ratio of 1:10 connecting said latter device with the next following device and so forth, so that the plurality of records :egresent respective decimal digits of said magni- 12. Apparatus for producing multiple strip chart records on a recording sheet, comprising means for accommodating and advancing the sheet; marking means having a single stylus means movable transversely of the sheet and a plurality of devices serially aligned in a direction transversely of the sheet for controlling said stylus to produce a corresponding plurality of marks within respective width portions of the sheet; means for moving said stylus so that said stylus sequentially engages said devices as it completes one stroke of transversal travel; and control means for adjusting said devices so as to displace the respective points along the stylus travel at which said stylus engages said devices.

13. Apparatus for recording a variable magnitude of a condition under observation, comprising means for accommodating and moving a record chart; marking means disposed for producing a curve on the chart and including a single-turn helical member revolvable about its geometrical axis and having an axial extent correlated to the width of the chart transverse to the moving direction of the chart so that different positions of revolution of said helical member correspond to different singular points respective across the width of the chart; unidirectional drive means connected with said helical member for revolving it in a given direction, and condition-responsive control means connected to said drive means for operating the latter at a variable rate dependent upon a condition under observation whereby a curve is recorded which crosses the chart repeatedly during the period of several complete revolutions of said helical member so that the number of crossings is indicative of the integral value of said condition.

14. Apparatus for recording a plurality of variable quantities in strip chart means, comprising mechanism for longitudinally advancing the strip chart means, a single stylus disposed for electrically marking a corresponding plurality of records on said chart means and being movable at an angle to the chart advancing direction across substantially the entire width of said chart means, a single contact element mechanically connected with said stylus so as to be movable simultaneously and in a given positional relation relative to said stylus in order to complete a given cycle of movement during each complete crossing movement of said stylus, said contact element being electrically connected to said stylus for transmitting mark producing impulses thereto, drive means for moving said stylus and said contact element repeatedly over the respective paths of cyclical travel, a plurality of conductive members serially aligned along the path of travel of said contact element so as to be sequentially contacted by said contact element as said stylus travels once across the chart means, electric circuit means connected to said conductive members for causing them to transmit mark producing electric impulses to said contact element and stylus, and a plurality of control devices responsive to said respective quantities and connected with said respective members for controlling the transmission of said impulses as said contact element travels along said respective members, in order to cause said stylus to mark during a sequence of crossings a plurality of separate records on separate strip positions of the chart means that extend in parallel to each other along said advancing direction.

15. Apparatus for recording a variable magnitude of conditions under observation, comprising means for longitudinally moving an electroresponsive strip chart, means disposed for electrically producing curve records on the chart and including a carrier movable across the chart at a right angle to the moving direction of the chart, said carrier having a stylus electrode for marking the chart and a single contact element connected with said stylus electrode; a plurality of circuit members extending serially aligned along the path of said carrier so as to be sequentially contacted by said contact element along the path of travel of the latter in order to impart to said stylus a corresponding plurality of successive electric marking impulses; and a corresponding plurality of condition-responsive electric control circuits connected with said respective members for controlling the transmission of said impulses as said contact element travels. 2

GEORGE KEINATH.

REFERENCES CITED The following references are of record in the file of this patentf UNITED STATES PATENTS Number Name Date 367,625 Haynes Aug. 2, 1887 1,278,964 MacGill Sept. 17, 1918 1,352,150 Schmeider Sept, 7, 1920 1,598,739 'Mettler Sept. 7, 1926 1,641,199 Rucka Sept. 6, 1927 1,676,848 Au July 10, 1928 1,784,522 Harrison Dec. 9, 1930 1,825,551 Serrell Sept. 29, 1931 1,909,142 Zworykin May 16, 1933 1,933,356 Warner Oct. 31, 1933 1,967,072 Young July 17, 1934 2,141,974 Finch Dec. 27, 1938 2,151,936 Pfiugner Mar. 28, 1939 2,232,589 Chappell Feb. 18, 1941 Q FOREIGN PATENTS Number Country Date 310,582 Great Britain May 2, 1929 

